 The zoo features more than 1,500 birds, mammals, amphibians and reptiles representing nearly 200 species. Exhibits include the state-of-the-art Polar Bear Watch, African Journey and the award-winning Children’s Zoo within the Maryland Wilderness.

 Outdoor panda exhibit of Mei Xiang and Tian Tian. Open to the public 9 a.m.-4:30 p.m. daily.

 Sea lion training and elephant care session. 11:30 a.m. most days.

 The Amazonia Science Gallery depicts a living river system, a rain forest and field-research exhibits. A biological diversity study center has a scanning electron microscope and a collection of live insects and amphibians.

Tudor Place Historic House and Garden

1644 31st St. NW. 202/337-5815.

 House and garden tours available Sunday afternoons and all day Tuesday-Saturday. $3-$6.

James Madison’s home and burial place on Route 20, four miles south of Orange, Va. 9:30 a.m.-5 p.m. daily for tours. Admission $3.50-$7.50. 540/672-2728.

Mount Vernon

George and Martha Washington’s home and burial place at the south end of George Washington Memorial Parkway. 8 a.m.-5 p.m. daily through October; 9 a.m.-4 p.m. November-February. $6-$13, children under 5 are free. 703/780-2000.

 Old Town Trolley’s two-hour day tours make 18 stops, including the White House, the Capitol and Arlington National Cemetery. Tours begin 9 a.m.-5:30 p.m. daily. $32 adults, $16 children, free for children under 3. Evening tours also available. 202/832-9800.

 Public lectures in the courtroom every half-hour 9:30 a.m.-3:30 p.m. when the court is not hearing arguments. Public seating for arguments when the court is in session is on a first-come, first-served basis on the day the court meets. Call ahead to confirm court meeting location.

 Year-round Sunday hikes using chartered bus with pickup points in the District, Virginia and Maryland. Monthly moonlight hikes on the C&O Canal from early spring to late fall. www.capitalhikingclub.org

Center Hiking Club

 Weekend and Wednesday evening hikes. 703/527-2349.

Freestate Happy Wanderers

 Walks every day on six trails through Maryland. 410/437-2164 or 301/490-5850 before 9 p.m. to request a brochure.